import numpy as np
import matplotlib.pyplot as plt

def f(x,y):
    return (1 - x/2 + x**5 + y**3)*np.exp(-x**2 - y**2)

n = 256
x = np.linspace(-3, 3, n)
y = np.linspace(-3, 3, n)
X,Y = np.meshgrid(x, y)

plt.axes([0.025,0.025,0.95,0.95])

plt.contourf(X, Y, f(X,Y), 8, alpha=.75, cmap=plt.cm.hot)
C = plt.contour(X, Y, f(X,Y), 8, colors='black', linewidth=.5)
plt.clabel(C, inline=1, fontsize=10)

plt.xticks([]), plt.yticks([])

# savefig('../figures/contour_ex.png',dpi=48)
plt.show()
